- 行业: Earth science
- Number of terms: 93452
- Number of blossaries: 0
- Company Profile:
Founded in 1941, the American Congress on Surveying and Mapping (ACSM) is an international association representing the interests of professionals in surveying, mapping and communicating spatial data relating to the Earth's surface. Today, ACSM's members include more than 7,000 surveyors, ...
(1) A tidal constituent having a period longer than one day. (2) A tidal or tidal current constituent having a period independent of the rotation of the Earth but dependent on the orbital movement of the Moon or of the Earth. The principal lunar long period constituents have periods approximating the month and half month, and the principal solar long period constituents have periods approximating the year and half year.
Industry:Earth science
A current that results from a difference in water level. Most natural currents are of this type.
Industry:Earth science
A legal instrument which, when executed and delivered, conveys an estate in real property or an interest therein.
Industry:Earth science
Any cycle related to the Moon's orbit, part-icularly the Callippic cycle or Metonic cycle. The synodic month, etc. , are also considered lunar cycles, although they are rarely referred to as such.
Industry:Earth science
(1) The set of constants specifying the coordinate system to which elevations are referred, or (2) the coordinate system specified by the constants. When vertical control is understood to refer only to elevations determined by geodetic leveling, the constants consist of the elevations which are known by definition (that is, independent of measurement by leveling). The vertical control datum (2) then consists of the points specified by the constants and the surface through these points as determined by leveling and adjustment. If only one elevation is specified, the datum is the geoid or an approximation thereto. If several elevations are specified, the surface is complicated and is neither the geoid nor mean sea level. When vertical control is understood to refer to elevations or heights determined by methods not involving the geoid (as, for example, heights determined by satellite geodesy), the datum is either the complete datum used for the survey or that portion of the datum sufficient for specifying elevations or heights. (3) Any level surface taken as a surface of reference from which to reckon elevations.
Industry:Earth science
The finest reading that can be made directly (without estimation) on a micrometer or vernier.
Industry:Earth science
A stake set by a surveyor, in running a survey by metes and bounds, set at every change of direction to assist the surveyor and to fix the survey to the ground.
Industry:Earth science
The complete set of tidal currents occurring during a specified cycle such as a tidal day, the Metonic cycle, etc.
Industry:Earth science
(1) The number of persons per unit area in a specified region. (2) The number of families (or occupants of building-type units) per unit area. (3) The number of building-type units per unit area.
Industry:Earth science
